In the above-referenced related prior patents, optical spectrophotometric procedures and apparatus are disclosed and described for in vivo clinical application to human patients, as well as a potential broader range of subjects, by which important biomedical information may be obtained which is directly indicative of intrinsic, internal biological and physiological processes, conditions, tissue or substance composition or state, etc., and these prior patents generally contemplate use of certain "optical probes", i.e., optical component groupings and their mounting and carrying apparatus, by which the selected light wavelengths are emitted and applied to the patient and the resulting light is detected and monitored at various locations on the patient.
While one principal focus of these prior patents involves the use of such spectrophotometric techniques on human anatomy in a manner by which the relative spacing of the light-emitting and certain of the light-detecting elements was variable, the underlying significance of such spacing was the important consideration in this regard, and thus the disclosures in these patents also contemplate comparable or analogous sender-receiver configurations of fixed geometry. These configurations and underlying considerations are particularly addressed in prior application Ser. No. 329,945, now U.S. Pat. No. 5,139,025 and in U.S. Pat. No. 5,217,013, which in some respects are more particularly directed to the use of such optical spectrophotometric procedures on the human head, in conjunction with examination of certain parameters and attributes of brain condition and function, in particular cerebral blood oxygen saturation. Accordingly, this last-mentioned copending application discloses and describes additional and other such "optical probes" or sensors which are particularly intended for (but not necessarily limited to) use on the human skull, for monitoring internal brain tissue and function through representative parameters.
The present invention is directed to improved and preferred forms of sensors for use in apparatus of the type just mentioned, as well as for potential use in other analogous such devices, providing further advanced and improved "optical probes" or patient interfaces, by which optical-response data is obtained from the patient and supplied to a spectrophotometric processing device. Prior participants in the art have addressed somewhat similar or analogous underlying considerations, and reference is particularly made to the work of Frans F. Jobsis et al, as represented in and by prior U.S. Pat. Nos. 4,223,680; 4,281,645; 4,321,930; 4,380,240; 4,510,938; and 4,805,623. While certain of the underlying concepts and/or scientific assumptions or theories set forth in these patents differ markedly from those addressed by the present invention, as reflected by the related and incorporated prior and copending patents and applications identified above, these prior patents attributed to Jobsis et al contain considerable information, etc. of interest to the general subject matter hereof, and certain such patents (in particular, U.S. Pat. Nos. 4,321,930, 4,380,240 and 4,510,938) expressly disclose patient sensor units in the form of headpieces for use in superficially similar in vivo optical spectrophotometric procedures. Accordingly, these and other such prior teachings provide background information of definite interest, and to some extent this may be said in connection with various sensors developed for use in arterial pulse oximeters and patented previously; for example, see U.S. Pat. Nos. 4,013,067, 4,865,038, 4,819,752, 4,825,879, 4,928,691, 4,880,304, 4,964,408, and published PCT Application WO 89/09566.